Continuous arc welding system



Dec. 26, 1944. Q J HOLSLAG 2,365,958

CONTINUOUS ARC WELDING SYSTEM Filed July 10, 1943 2 Sheets-Sheet 1Zhwentor XQZ ZQQQ (J a pwzg Clttorneg Dec. 26, 1944. c J HOLSLAG2,365,958

CONTINUOUS ARC WELDING SYSTEM Filed July 10, 1943 2 Sheets-Sheet 2Enventor (fol-neg Patented Dec. 26, 1944 CONTINUOUS ARC WELDING SYSTEMClaude J. Holslag, South Orange, N. J., asslgnor to Electric Arc, 1110.,

Newark, N. J.

Application July 10,1943, Serial No. 494,140

8 Claims.

This invention relates to a continuous arc welding system wherein thework or pieces to be welded are continuously moving and the weldingelectrode and associated apparatus is stationary, or vice-verse, andwherein the current used is much greater than in normal manual welding,and the arc is covered by a thick blanket of flux which is usuallyapplied and removed as the welding progresses.

In such welding systems it is the usual practice to try to complete theweld in a single pass by using an electrode of relatively large diameteras compared to normal manual welding, and.a heavy current whereby agreat amount of metal may be laid down in a single pass. In such an arcwelding system the supply voltage is usually on the order of 80 volts orsomewhat more, of which approximately 40 volts are used in the arc andthe balance in a reactor connected in series with the arc. Hence, theenergy consumed in the reactor is waste.

Under the conditions mentioned above, there are quite apt to beexcessive strains applied to the area in and around the Weld, and it isthere fore the principal object of my invention to provide means foreliminating these stresses.

While eliminating the stresses, it is another object of my invention toimprove the operating eificiency of the entire system by utilizingpower, which has heretofore been wasted in the usual type of reactor, asa preheater for condi tioning the metal to be welded so as to preventstrains which are set up during the welding operation.

The attainment of these objects will be best understood by reference tothe annexed drawings, wherein:

Figures 1 to 5 inclusive illustrate test pieces that I have prepared andtested to demonstrate the correctness of the disclosures which are tofollow.

Figure 6 illustrates, diagrammatically, one

form in which my improvements may be applied.

Figure 7 shows a further form of application of my invention.

Figure 8 illustrates a still further form.

Figure 9 shows, somewhat diagrammatically, the construction of one ofthe units utilized in my improved system.

Figure 10 is a View on the ure 9.

Figure 11 is a perspective view of a unit used in my improved system.

line Ill-Ill of Fig- ,steel plates 2H" thick Where the materials weldedare of Figure 12 is a side view in the direction of the arrow of thestructure shown in Figure 11.

Referring now to the drawings, in Figures 1 to 5 inclusive, which weremade from photographs of original test plates, l and 2 are two weldedtogether by a A electrode utilizing, in each case, 360 amperes. Inmaking a weld oi the type shown, approximately iliteen passes or beadsare required to complete the weld. In Figure l, the approximatetemperature between beads or weld layers was held at degrees F. Afterthe weld was completed, it cracked as indicated in the drawings.

'In Figure 2 the temperature between the beads was maintained at 2%degrees F. with the result shovm in the drawings.

In Figure 3 the temperature between the beads was held at 30d degreeswith the result as.

shown.

In Figure 4 the temperature between the beads was held at dill degreeswith the result as indicated.

In Figure 5 the temperature was held at 500 degrees F., showing that atthis temperature no apparent strains or stresses were up and left in theweld or the material adjacent thereto.

These tests, together with others which ii have made, clearly indicatethat care must be exercised in making welds to avoid stresses in theweld area; especially is this true where large electrodes and heavycurrents are used, and the alloy type. Consequently, pre-= andposi2-heating must be performed according to the materials to be weldedand conditions surrounding the same.

In Figure 6 a tube 3 is to be welded along the seam t. This weldingoperation is performed by an electrode 5 red, in any satisfactorymanner, through a nozzle 6 through which an excess quantity of flux 1 ispassed from the source of supply by means 01' the pipe 8 so that the arcis covered or blanketed by a relatively thick layer of flux, the excess,not used up in the welding operation, being picked up by the hood 9 anddelivered by a pipe 10 to a receiver. This laydown and pick-up apparatusfor the flux may take some other form than that shown which is somewhatas indicated in my Patent 2,105,079, issued January 11, 1938. Thecurrent supplied to the electrode 5 by means of any suitable slidingcontact ii, is connected through a reactor R to the secondary S of atransformer '1" having a primary 1? connected to a suitable sou ce clpower.

One end of the secondary S is electrically connected to the tube 3 bythe carriage containing it, or by a sliding contact such as indicated atH. Another transformer T, having a primary P and secondary S, furnishescurrent to a preheating structure l3, but is connected to a post-heaterM. If necessary, some form of impedance I! may be utilized in thisheating circuit. The preand post-heaters l3 and II are preferablyconstructed in a manner to be hereinafter described, but the mainfunction of the preheater i3 is to bring the metal to be welded up to asuitable temperature so as to eliminate, as far as possible, the strainsin the metal around the weld area and any strains, remaining thereinafter the welding, are removed by the postheater H.

In Figure 7 I have entirely eliminated the reactor R, and its supplytransformer T, and the transformer T furnishes its power directly to thepreand post-heaters i2 and I4 which serve a dual purpose of heaters andreactors.

In Figure 8 the preheater I3 is in the form of a transformer having aprimary l8 and a secondary H. The secondary I1 is connected to theelectrode 5 and also to an auxiliary pre-heater i8 which is preferablyutilized to step up the temperature as determined by the preheater 18.In this case the preheater l3 acts as a heater and a reactor. Also, theauxiliary heater l8 has a steadying effect in multiple across the arc,especially so if bridged by a suitable capacity. In the arrangement ofFigure B, the post-heating structure H may be used if the type of workrequires it. A switch 88 may be included in its circuit.

In Figures 9 and 10 I have shown, somewhat diagrammatically, a heaterand reactor unit positioned over two flat plates l8 and which are to bewelded together along the seam 2|. This unit includes a coil 22 oi a fewturns of large wire; for example, for many classes of work I have foundsix turns of 500,000 circular-mil cable to be satisfactory forpre-heating.

Positioned in the central part of the winding is a core 23 of suitablelaminated magnetic material such as transformer stock, and extendingtransversely across the core are a plurality (for the sake of simplicityonly three are shown) of cross-bars 24 of similar laminated stock; andextending downwardly from the ends of the bars 24 are legs 25 of similarlaminated material. The legs 25 and the central core 28 are all shown inFigure 10 as flush with the lower plane of the coil 22 and in contactwith the pieces I! and 20 that are to be welded together. The nearer thecoil 22 is to the pieces, the greater the heating effect, but inpractice. where the structure is mounted within a casing 28 of suitableinsulating material, such as Transite, the c0il 22 may be a slightdistance inwardly from the plan of the end of the leg 25, and thecentral core 28, in order to have some protection from the elements.Relative adjustment may also be provided between the winding 22 and thecore members to change the heating and reactive eflects.

As shown in Figure 11, the casing 28 is provided with four trucks 21which are adjustably mounted by the members 28 so as to position thecoil 22 to give the desired heating and reactance effect. In addition,the coil 22 may be arranged in two sections, with the terminals broughtout at 29, 30, 3| and 32, whereby they may be connected in series or inparallel for current and reactance regulation. In some cases, thestructure of Figure 11 may contain a primary winding such as I 6 shownin Figure 8 and indicated by the cross-dotted lines 33 in Figure 10. Inthis case, the primary winding may be divided into two parts which maybe connected in series or parallel for utilizing a 440 or 220-voltprimary, with taps on each section, these terminals being indicated atN.

The casing 20 is also provided with lugs 35 for receiving grab-hooks orthe equivalent for moving the heater-reactor structure to any desiredlocation. The particular design shown in Figure 11, although forming nopart or my present invention, is very useful in its application thereto.

While' I have shown the combined preand post-heaters and reactors asexteriorly positioned with respect to the parts to be welded, they maybe mounted interiorly and of course formed to suit the structure to bewelded.

It is obvious that many of the details for carrying my invention intopractice may be varied over a considerable range without departing fromthe spirit of the same; for example, the laminations used in theconstruction of Figure 9 may be E-shaped, which it may be advisable touse instead of the form shown.

What I claim is:

1. In a continuous arc-welding system in which the arc current is muchgreater than in normal manual welding and the arc is covered by a thickblanket of flux which is applied to the weld area and removed as thewelding progresses, means for eliminating strains in the metal set up bythe welding operation, said means including at least one preheating coilstructure positioned on the material Just in front of the area to bewelded, and a post-heating coil structure positioned on the materialJust back of the welded area, said coil structures being relativelymovable along the entire length oi the seam to be welded and havingadjustments whereby their heating effects may be regulated to suit thewelding operations.

2. In a continuous arc-welding system in which the arc current isrelatively great and the arc is covered by a thick blanket of flux whichis applied and removed as the welding progresses, means for eliminatingtroublesome strains in the metal set up by the welding operation, saidmeans including at least one preheating coll structure positioned on themetal in i'ront'of the area to be welded, said coil structure beingrelatively movable along the entire length of the seam to be welded andhaving adjustments whereby its heating effect may be regulated to suitthe welding operation. I

3. In a continuous'arc-welding system in which the arc current isrelativelygreat and the arc is covered by a thick blanket of flux whichis applied and removed as the welding progresses, means for eliminatingtroublesome strains in the metal set up by the welding operation, saidmeans including at least one preheating coil structure positioned on themetal in front of the area to be welded and having relative movementalong the entire length of said area, said coil structure beingconnected into the arc circuit to act as both a preheater and areactance for controlling the arc.

4. In a continuous arc-welding system in which the arc current isrelatively great and the arc is covered by a thick blanket of flux whichis applied and removed as the welding progresses. means for eliminatingtroublesome strains in the metal set up by the welding operation, saidmeans including at least one preheating coil a preheater and aregulating reactance for the arc.

5. In a continuous arc welding system in which the arc current isrelatively great and the arc is covered by a thick blanket of flux whichis applied and removed as the welding progresses,

means for eliminating troublesome strains in the metal set up by thewelding operation, said means including two preheating coil structurespositioned in tandem relationship on the metal in advance or the arc,the coil structure farthest from the are being connected into the arccircuit to act as a reactance therein as well as a preheater, while theother coil structure nearest the arc acts as a preheat step-up.

6. In an arc-welding system, means for eliminating troublesome strainsin the metal set up by the welding operations, said means including atleast one preheating coll structure adapted to be positioned on themetal in front of the area to be welded and having relative movementalone the entire length of said area, at least a portion of said coilstructure being connected into the arc circuit to act as both apreheater and a re actance for controlling the arc,

7. In a continuous arc-welding system in which the arc current isrelatively great and the arc is covered by a thick blanket of flux whichis applied and removed as the welding progresses, means for eliminatingtroublesome strains in the metal set up by the welding operation, saidmeans including two preheating coil structures positioned in tandemrelationship on the metal in advance of the arc, one of said coilstructures acting as a preliminary heater while the coil structurenearest the arc acts as a preheat booster, the arc current being takenoiI ahead or the heat booster coil structure, a post-heater coilstructure positioned directly after the weld, one

or more of said coil structures having adjustable parts for varying theheating and reactance efrects thereof.

8.- In an arc-welding system, means for eliminating troublesome strainsin the metal set up by the welding operations, said means including atleast two heating coil structures adapted to be placed on the metalbeing welded in close proximity to the arc area and being relativelymovable thereon along the entire length or said area, at least some partor one of said structures adapted to be connected into the arc circuit.

CLAUDE J. HOLSLAG.

